Suction relief-valve.



J. T. ATWOOD.

SUCTION RELIEF VALVE.

APPLICATION mm APR-23.1914.

1,156,872, Patented Oct. 19, 1915.

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JAMES T. .ATWOOD, F ROCKFORD, ILLINOIS.

SUCTION RELIEF-VALVE.

To all whom it mag concern;

Be it known that I, JAMES T. A'rwooD, a citizen of the United States, residing at Rockford,'in the county of l/Vinnebago and State of Illinois, have invented certain new and useful Improvements in Suction Relief- Valves, of which the following is. a specification.

This invention relates to the general art of relief-valves and more particularly to those employed in vacuum cleaning systems or other apparatus where suction is used.

In vacuum cleaning apparatus it is eustomary to provide an exhauster operable by suitable power driven means for producing vacuum in a receptacle to which dust and dirt laden air is drawn by the vacuum through tubes from the points otcleaning, the dust and dirt in whole or in part being retained in the receptacle and the'airwith dust, if any, being drawn to the vacuum producer and discharged therefrom. -When the cleaning operation is interrupted the air inlet to said receptacle is shut off thereby causing a strong vacuum to be developed in the receptacle, which imposes an excessive and undesirable load upon the vacuum pro-V ducer and driving means. VVith the View of obviating this diihculty it has been oustomary to provide the vacuum receptacle or the vacuum line with an ordinary reliefvalve adapted when a predetermined vacuum is attained to automatically open and permit inflow of air thereby relieving the vacuum producing mechanism of unnecessary burden and the driving mechanism of undue strains.

One of the primary objects of my invention is to provide .a suction operated reliefvalve which will automatically open and permit intake of air into a vacuum cleaner chamber when a predetermined maximum suction has been developed, and which having been opened will be retained in open position by a considerably lesser suction force than is required to initially-open it, thus materially reducing the strain on the vacuum producer and diminishing the power re quired to drive it.

Another object is the provision of a suetion operated valve which will perform the desired functions with accuracy and precision and which will be simple in constructionand cheap to manufacture.

A valve of this character applied to a vacuum system as has been described, auto- Specification of Le'tters iatent.

maticallyqa-dmits air to the vacuum receptacle ;or vacuum line when a vacuum of a predetermined number of inches has been created-therein, and efiiects a rapid reduction in the vacuum to a predetermined amount thereby materially reducingthe load on the vacuum producing mechanism. 1 1

In the accompanying drawings, Figure l isa view in elevation of part of a vacuum cleaning system embodying my invention.

Patented one. 19;, 1915.-

, Application filed Apri1-23, 1914. Serial N 0. 833,998.

Fig.2 is :an enlarged verticalsectional view through the relief-valve, and Figs. 8, 4,.and 5 .aretransverse sectional views through the relief-valve taken on the lines 33, M, and 55 respectively of Fig. 2. V

By reference to the drawings it will be observed that a vacuum producer Gadapted to be driven by suitable power-means, isconnectedthrough the pipe 7 with a receptacle or chamber 8 in which vacuum is maintained by :the producer and to which dust and dirt laden air is drawn through the suction pipe 8 from the usual nozzle or cleaningtool (not shown), the dust and dirt in whole or in part beingseparatedfrom the air and retainedin the'reeeptacle while the air with dust, if any, is drawn therefrom to the vacu= um producer and discharged to the outer atmosphere and preferably to a sewer. The relief-valve embodying my invention is preferably threadedinto the topof the receptaole and is adapted to automatically control the amount of vacuum created therein by the producer.

I The relief-valve as shown comprises a casing 9 screw-threaded into-the top of the receptacle 8, and providing a circular chamber 10 opening into the receptacle. The transverse wall forming the top of the chamber is provided with a reduced opening 11 through which communication is established between the chamber 10 and the atmosphere, said opening 11 being shaped to provide a tapered or beveled valve-seat at, its under side. A valvedisk 12 carried by the stem 13 cooperates with the valve-seat to close the centrically within the chamber 10 and presenting a surface of greater area than the top of the valve-disk, and of less area than the cross-sectional area of said chamber 10, the peripheral edges of the flange being spaced from the adjacent walls of the chamber to provide a passage 17 surrounding the flange.

When the valve is closed the upper face of the disk or flange 16 is spaced from the top wall of the chamber 10 and when the valve is open the disk 16 will be disposed beneath the lower edges of the side walls of the chamber. The length of chamber 10 is such that with the disk 16 held in open position the valve 12 will give opening 11 a full area opening.

Assuming for purposes of illustration, that the maximum vacuum which it is desirable to induce is 8 inches of mercury when the systemis in use, it will be evident that if the use of air is discontinued by shutting oil the suction pipe, a vacuum in excess of the desired maximum will be produced in the receptacle by the producer, which will cause the latter to operate under an excessively heavy load unless this excess is relieved by a relief-valve or other similardevice. If an ordinary relief-valve set to open under 8 inches of vacuum is employed, the valve will open when the desired maximum vacuum is reached but it will close again when the vacuum falls slightly below the maximum, with the result that a high vacuum approaching the maximum will be maintained as long as the machine runs with the suction closed or nearly closed.

With the relief valve set forth in this invention when the use of air is discontinued in whole or in part the vacuum may rise to the desired 8 inches and at this point acting on the of valve 12 it overcomes the resistance of the spring 15 and admits air of atmospheric pressure into chamber 10 above disk 16. The vacuum in the tank now acts upon the larger area of disk 16 and allows air to enter more freely so that the vacuum drops materially to apredetermined amount depending upon therelative areas of 12 and 16 to about 1 inches." Thus the strain on the producer and the power required are mate rially lessened by the use of this valve. In order that the valve will close readily when more air again enters the system through the cleaning hose, the area of passage 17 must be adjusted approximately for the air capacity of the vacuum cleaner system upon which it is used. This area 17 is slightly smaller than the area between the lower edge of chamber 10 and the upper edge of disk 16 when all the air is entering through the Copies of this patent may be obtained for valve. When a very small amount of air enters the system elsewhere the area between these two edges is reduced accordingly but the valve remains open so long as this area is greater than area 17. Only a comparatively small amount of the total air needs to enter elsewhere such as through the cleaning hose to reduce the area between these'two edges down to the size of area 17 at which point the pressure of the spring overcomes the action of the vacuum on disk 16 and the valve closes. Under ordinary conditions the closing will take place when the vacuum has been reduced to about 4 inches; It will thus be apparent that the valve cannot remain in an approximate balance so as to flutter between open and closed positions.

Vfhile I have described an illustrative eX- ample of relative suction forces for the pur pose of explaining the use of my improved suction valve, it is obvious that the propertions and sizes of the valve surfaces, the passages, and spring may be varied to effect difi erent ranges of maximum and minimum suctions controllable by the valve.

1 claim as my invention:

A suction relief-valve comprising a cylindrical casing adapted to be connected with a' vacuum system, said casing providing a chamber open at its inner end and having an outer end wall provided with a port surrounded by an inwardly facing valve-seat, a valve-stem extending through said port, a valve-disk carried by said stem having its outer end shaped to lit said valve-seat and provided at its inner end with a radially disposed anrular flange spaced from the surrounding walls of said chamber and presenting an outer surface of greater area than the effective area of said port and disposed within said chamber above the lower edges of the chamber walls when the valve is in closed po sition, means outside the chamber for guiding said valve-stem, and a spring acting on said stem to normally urge the valve toward its seat, the area of the space between the periphery of the flange and the surrounding chamber walls being less than the effective area of said port so that the flange is moved inwardly beyond the ends of the chamber walls whenthe valve is initially opened and serves to retain the valve in open position so long as the area of the space between said ends of the chamber walls and said flange exceeds the area of said space between the periphery of the flange and the surrounding chamber walls. I

JAMES T. ATVVOOD. Witnesses MILDRED E. LINTON, COURTLAND K. WHITE.

five cents each, by addressing the Commissioner of latents, Washington, I). C. p 

